Spark-coil



J. F. CAVANAGH.

SPARK COIL.

APPLICATION FILE'D AUG.15,1918.

Patented May 4, 1920.

UNITED STATES PATENT OFFICE.

JOHN CAVANAGH, 0F MERIDEN, CONNECTICUT, ASSIGNOR TO CONNECTICUT TELE- PHONE & ELECTRIC COMPANY, INC., OF MERIDEN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

SPARK-COIL.

Application filed August 15, 1918.

T 0 all whom it may concern:

Be it known that I, JOHN F. CAVANAGH, a citizen of the United States of America, residing at Meriden, Connecticut, have invented a new and useful Spark-Coil, of which the following is aspecification.

My invention relates to spark coils of the type used for the ignition of internal combustion engines.

The objects of the invention are to simplify and cheapen the coil structure, to improve the same both from a mechanical and an electrical standpoint, and to facilitate assemblage and testing of the coil.

One of the features of the invention consists in mounting the electrical elements of the coil, including the terminals, primary and secondary windings and condenser, all on a single base, apart from the casing, adapted to be handled and tested as a complete electrical unit before having the casing applied thereto.

Another feature of the invention is a method of securing the casing to the switch base supporting the other electrical parts by means of a single through bolt which serves also as the means for fastening the condenser and the coil windings on the back of being water-proof, oil-proof, etc.

Other features of the invention will appear as the specification proceeds.

In the accompanying drawing, I have illustrated the invention embodied in one of its practical commercial forms, it being understood that the form of the invention may vary without departure from the true spirit and scope thereof.

In this drawing:

Figure 1 is a longitudinal sectional view of the complete coil structure.

Fig. 2 is a more or less diagrammatic view illustrating the electrical connections of the same.

Fig. 3 is a view of the complete electrical unit separate from the casing.

The base or support 5 for the electrical elements of the coil is illustrated in the form of a relatively fiat disk-like member adapted to form an end cap for the completed coil.

According to my invention, this base is constructed of porcelain or other insulating Specification of Letters Patent.

Patented May 4, 1920.

Serial No. 250,018.

material of this nature and which is both that porcelain can be molded to the requisite shape and can be given a smooth glassv surface which will cause it to shed both water and oil and will prevent the accum u latlon of dust, etc., thereon. In addition to its h1gh insulating qualities, porcelain is also relatively cheap and plentiful and possesses the necessary strength as a supportfor the parts attached thereto and about t be described.

Mounted on the face of the porcelain end cap or base are the terminals 6, 7 8 and 9, the latter being the high tension terminal, and the others being the battery and primary terminals.

Mounted on the back of the porcelain base are the primary and secondary windings 10, 11, the core 12 and the condenser 13.

The core, which may be made up of a bundle of iron wire as customary, is shown let into a recess in the back of the base, and the primary and secondary windings are shown supported directly upon this core.

The condenser is shown constructed in the form of an open center coil made up, for instance, of alternate layers of paper and metal foil. This condenser coil is located at the end of the coil windings, and therefore, removed to a large extent from the influence of the high tension generated by the secondary. In the particular construction shown, the condenser is disposed co-axially with respect to the coil windings, being supported upon the end of the core, which is extended beyond the ends of the coil windings. The coil windings and the condenser are thus all supported on the magnetic core, and this core is shown secured to the back of the porcelain base by a single securing device in the form of a screw rod 14 made fast to the base by a nut 15, said rod having a shoulder 16 near the opposite end thereof engaging the end plate 17 of the core. This condition of the parts with all the electrical elements supported on a single base, is illustrated in Fig. 8, wherein the base with the terminals, windings and condenser all.con-= stitute a single unit which is electrically complete and can be tested and adjusted before being mounted in its protective casing. The protective casing consists in the present disclosure of a casing sleeve 18 of insulating material which is slipped over the electrical elements into engagement with the back of the base so as to provide an annular chamber 19 about said elements to receive a filling composition of suitable insulating material. This insulating material is usually melted and poured into the casing while hot, it hardening or setting as it cools to retain the parts in their relative positions and properly insulated from each other. An end cap 20 usually of metal is used to close the open end of the casing after the filling material has been applied thereto and this end cap is shown secured in place by means of a nut 21 engaged with the threaded extended end 22 of the securing bolt 14. The securing bolt is thus utilized also as a means for securing the casing in place.

The electrical connections will possibly be more clearly understood from the diagrammatic view, Fig. 2, wherein the opposite ends of the primary winding are shown connected by leads 23 and 24 with the terminals 7 and 8, one end of the secondary being connected by a lead 25 with the high tension terminal 9, and the other end of the secondary being connected by a lead 26 with one of the terminals 27 of the condenser. Also connected with this condenser terminal 27 is a grounding wire 28 which is shown as bare or non-insulated and as extended up through the bundle of iron wires constituting the core into connection at its upper end with the terminal 6. The other terminal 29 of the condenser is connected by an insulated wire 30 with the primary lead 23. This insulated wire 30 is also extended up through the core but by reason of its insulating covering is insulated therefrom.

The metal end cap 20 is usually grounded, as indicated in Fig. 2 to provide the ground side of the apparatus, the grounding being affected from the non-insulated wire 28 through the body of core wires to the core bolt 14, which bolt, as shown in Fig. 1, is in electrical contact with the end cap 20.

I claim:

1. A spark coil comprising a. casing and an electrical unit complete as such, independent of the casing, and adapted for testing before being assembled in the casing, said unit comprising an insulating base, terminals mounted on the front of said base, coil windings, a condenser supported by said coil windings, the said condenser and coil windings being supported on the back of said insulating base and electrically con- Iioiected with the terminals on the front of the ase.

2. A spark coil comprising a base of insulating material, terminals on the front of said base, coil windings and a condenser supported on the back of said base and electrically connected with the terminals on the front of the base, the whole forming an electrically complete single structural unit, a casing adapted to be applied over the electrical elements on the back of the insulating base, and means for securing said casing in position on the back of said insulating base.

3. A spark coil comprising, a magnetic core, primary and secondary windings on said core, an insulating head at one end of the core, terminals on said head, a condenser at the opposite end of the core and connecting wires extending from the terminals through the core to the terminals of the condenser, one of said connecting wires being insulated from the core and the other connecting wire being electricall connected with said core to thereby provi e a ground connection.

4. A spark coil, comprising a magnetic core, primary and secondary windings on said core, an insulating head at one end of the core, terminals on said head, a condenser at the opposite end of the core, connecting wires extending from the terminals through the core to the terminals of the condenser, one of said connecting wires being insulated from the core and the other connecting wire being electrically connected with said core to thereby provide a ground connection, a bolt extending through the core and securing said core to the terminal head, said bolt having electrical connection with the core and an end plate secured to said bolt and providing a ground plate for the coil.

5. In a spark coil construction, the combination of an insulating head having a passage extending therethrough with an enlarged portion at each end of the passage, a terminal socket member riveted into said passage, a core, and coil windings thereon, one of the terminals of the coil windings being secured to said terminal socket member.

6. In a spark coil, an insulating head having a central passage with an enlargement at the outer end of said passage, a core, coil windings thereon, external binding terminals carried by said head, a base, a central connecting rod passing through said core and said base, and an interiorly-threaded nut having a flanged outer portion seated in the enlarged entrance to the passage in said head and screwed onto the outer end of said ro 7. In a spark coil construction, an insulating member, a terminal socket carried thereby, a plurality of binding terminals carried by said member, a core rigidly secured to said insulating member, primary and secondary windings secured to said core, one surrounding the other, the ends of the windings being secured, respectively, to said terminal socket and said binding terminals, an insulating casing surrounding said coil windings, and means for securing said casing in position independently" of said coil windings, whereby the coil windings and the insulating member are adapted to be handled as a unit, independently of the casing.

8. In a spark coil construction, the combination of an insulating head having a peripheral groove in its under face, terminals on said head, a core, primary and secondary windings supported on said core and connected to said terminals, a sheet metal base plate having a centrally raised portion and a flaring flange, an insulating casing having its upper end seated in the groove of said insulating head and having its lower end centered by said centrally raised portion of said base plate, a centrally-disposed rod passing through said core, and a clamping member in the outer face of said insulating head and adjustable on said rod.

9. In a construction of the character described, an insulating head, circuit terminals accessible at the outer face thereof, a core, primary and secondary coils mounted on said core, one around the other, a condenser centered on one of said coils, a base plate, a casing centered by said head and said base plate, a central rod passing through said base plate and through said core and having its upper end accessible through said head, and a clamping nut on the outer end of said rod in said head and accessible from the outer face thereof.

10. In an articleof manufacture, a head for a spark coil, said head being formed of insulating material and provided with a central opening for a clamping nut and having a peripheral groove in its under face to receive the upper edge of an insulating casing and having passages for a plurality of binding screws extending therethrough, a terminal socket member riveted in said head, and an upwardly projecting insulating flange surrounding the entrance to said terminal socket member.

JOHN F. CAVANAGH. 

